The present disclosure relates to the field of automated level and density measurement systems for fluidized bed applications. Specifically, this disclosure generally relates to improvements to prevent blockage in conduits and nozzles used in fluidized bed applications by providing an automated computer operated purge system and methodology. In embodiments, a conduit may, for example, be a tube or a pipe. In embodiments, the conduit may be a tube or pipe made of metal, such as a stainless-steel, with a diameter of about 1/16″, ⅛″, ¼″, ⅜″, ½″, ¾″, 1″, or 1″ to 2″, or greater. In embodiments, a conduit may be used to connect one area of an operating facility to a sensor, such as a pressure sensor, differential pressure sensor, freeboard pressure sensor, level sensor, density sensor, or a fluidization grid differential pressure sensor for the measurement of pressure.
Blockage, or clogging, of conduits that are used to measure pressure within a vessel poses a serious problem to plant operations. Erroneous differential pressure readings which results from clogging, plugging, blocking, or bridging are difficult to identify and quantify in magnitude because of the many factors contributing thereto. False readings may also be due to leaks in conduits, ruptured conduits, loss or change in flow rate of purge gas. However, blockage of solids within a nozzle or conduit poses the most serious problem because of the difficulty of its detection.
Conduits may at times have the tendency to becomes blocked, clogged, bridged, or plugged with solids, frozen liquids, condensed tars, or particulate heat transfer material. Some blocking mechanisms include condensation of water within a conduit or network of conduits. In cooler climates, if relatively long conduit runs are installed and exposed to the elements of nature, freezing of condensation or liquid may also occur which may result in rupture of the conduit.
Blockage of conduits used for measurement of a pressure causes fluid bed pressure, level, and density information to be lost, with potentially serious consequences in a process control application. Avoiding blockages is a primary aim of the present disclosure. Avoiding blockages is of paramount importance to the reliability of fluidized bed systems to continuously operate in an unimpeded manner.
Without an automated level and density measurement system, a plant operator might have to physically and periodically locate themselves at a particular location in the facility to manually increase the flow through a conduit to periodically to dislodge blockage or prevent blockage conditions that may be taking place within the conduit. The manual process of physically manipulating and increasing the flow of gas through the conduits is unsustainable, unreliable, and time-intensive, often having to take up to twice a shift on a 12-hour shift to complete a trivial task. In the event an operator does not make his/her rounds to purge-out downstream conduits, the conduit will become clogged, rendering the connected instrumentation useless. And it is nearly impossible to operate a fluidized bed in a proper manner without differential pressure, level, and density data.
There exists a need to automatically periodically clean conduits used to measure pressure in fluidized bed applications during normal operation. This may be accomplished by use of a computer operated network of valves and conduits to provide an instantaneous, high flow, high pressure, high-volume burst of pressurized gas to the conduits and nozzles and into the interior of the vessel. During the time for purging conduits, differential pressure instruments or sensors may be isolated from the vessel and configured to momentarily not read the pressure of within the interior of the vessel. Instead, for a sudden instantaneous moment of time, a supply of pressurized gas is provided to the network of conduits to dislodge any blockages that may have deposited therein.